For the first time since 2015, Cinco de Mayo is a Tuesday, traditionally a day of taco specials.

But get this: Restaurants that use “Taco Tuesday” in their marketing may find a cease-and-desist letter from a lawyer in their mailboxes.

That’s because even though restaurants everywhere use the term, it’s trademarked. In 1989, the Wyoming-based Taco John’s chain got the federal rights for “Taco Tuesday” that cover every state except for New Jersey. In a quirk of law, Gregory’s Restaurant & Bar in Somers Point, which registered “Taco Tuesday” in 1982, has the exclusive for New Jersey because it does not transact business across state lines.

Keeping a trademark is the meat of the matter, which is why the owners sic their lawyers on bars and restaurants that use the term.

The Philadelphia-based Chickie’s & Pete’s sports bar chain dings other restaurants that advertise Old Bay-seasoned fries as “Crabfries,” which it trademarked in 2007. In an ironic twist, Chickie’s & Pete’s advertises Taco Tuesday promotions of its own.

In these unique times, the idea of truly enjoying Cinco de Mayo at a bar with tacos and margaritas (or — ah — a Corona or two) is out of the question. Many restaurants are selling bottles of beer and wine to go. Pennsylvanians cannot legally sell mixed drinks to go. Though the state House recently approved legislation, the bill won’t hit the Senate for a vote till it reconvenes on May 11.

Some restaurateurs are skirting the law by giving away margs with large taco purchases.

Here are a few taco highlights in the region besides the $36 family-size taco packages sold as Taco Tuesday (and Thursday) specials at Gregory’s and the lamb tacos from South Philly Barbacoa, which is not open on Tuesdays. However, Casa Mexico, SPB’s sibling at 1134 S. Ninth St., will have tacos on the menu.

Also, Inquirer food critic Craig LaBan spills plenty of taco tips in his roundup of South Philadelphia’s Mexican restaurants.

Lolita (106 S. 13th St.) reopens for takeout and delivery on Tuesday. Among the dishes are Tijuana-style “quesabirra” tacos with braised short rib. The tortillas are dipped in guajillo-ancho salsa and then hit the griddle.

Cantina Feliz in Fort Washington/Taqueria Feliz in Manayunk/La Calaca Feliz in Fairmount. The trio of cantinas split ownership last year, and you must order at specific locations. Cantina (424 S. Bethlehem Pike, Fort Washington) has a pickup traffic pattern in its parking lot. Taqueria (4410 Main St.) offers pickup and delivery, and La Calaca (2321 Fairmount Ave.) offers pickup.

Central Taco (now operating out of Pour House, 124 Haddon Ave., Westmont) sells tacos a la carte; the coconut shrimp is highly recommended.

El Limon (various locations in the burbs) turns out tasty tacos al pastor. Here’s a tip after the lockdown is over: the restaurant offers comp margaritas for dine-in.

Estrella Taco Bar (202 E. Lancaster Ave., Downingtown) sells cocktail mixers (individual and larger sizes), as well as their family packs of six tacos.

La Peña Mexican Taqueria (609 W. Cypress St., Kennett Square) is doing pickup; everything on the menu is recommended — the fish, shredded pork, and chicken tinga in particular. Your challenge is finding a menu online; best to call 610-925-2651 and state your Mexican food of choice.

Los Camaradas (918 S. 22nd St.) is running its full menu; pay attention to the Baja fish and pork belly tacos.

The Ripplewood (29 E. Lancaster Ave., Ardmore) for tongue-and-cheek tacos.

Tamarindo’s (726 Bethlehem Pike, Flourtown) reopens Tuesday with curbside pickup. Among the specials are $30 taco bundles for two. Caution: The regular dinner menu is still live on its website, but it’s operating with a scaled-down one.